JPH11249464A - Mechanism for stretchingly setting endless film and heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the tension force of an endless film and to stabilize the function of a film surface abutting member. SOLUTION: This mechanism arranged inside a heat fixing device 20 is provided with an endless belt 31 laid between at least two winding members 32 and 33 and rotating, and the film surface abutting member 35 giving the tension force to the endless film by being pressed by pressuring force on the outside peripheral surface of the belt 31. In this case, a pressuring member 50 giving the pressuring force to the member 35 is supported by the members 32 and 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless film stretching mechanism and a heating apparatus having an endless film (including an endless belt) which is wound around at least two winding members and rotates. The present invention relates to an endless film stretching mechanism and a heating device including a film surface abutting member that applies tension to the endless film by being pressed against an outer peripheral surface.

[0002]

2. Description of the Related Art As an apparatus using an endless film stretching mechanism having an endless film which is wound around at least two winding members and rotates, there is, for example, a heat fixing apparatus of a film heating type. Is known, for example, from JP-A-8-334997. As shown in FIG.
This is a so-called fixing belt type heat fixing device, in which an endless belt 100 is wound around a fixing roller 101 and a heating roller 102, and a pressing roller 103 is pressed against the fixing roller 101 via the belt 100 by an urging force of a spring 111. It was used and pressed. The heating roller 102
Is provided with a heater 108, and is urged by a spring 107 in a direction away from the fixing roller 101, so that the endless belt 100
Tension. In this example, when the fixing roller 101 is driven to rotate in a direction indicated by an arrow n by a driving unit (not shown), the endless belt 100 is also driven in the same direction, and the heating roller 102 and the pressure roller 103 are driven to rotate. The endless belt 100 has a heating roller 102 in an upstream area of a nip 112 between the belt and the pressure roller 103.
Preheated. The transfer paper S on which the toner image has been transferred is passed through the nip 112, where the toner image is fixed on the transfer paper S by the heat of the endless belt 100 and the pressure between the belt and the pressure roller. Sent to

The endless belt 100 includes a spring 11
In many cases, the film surface contact member 104 receiving the elastic force of No. 3 comes into contact. The film surface abutting member 104 is used for cleaning means for removing dirt due to paper dust, toner and the like adhering to the endless belt 100, or for suppressing a so-called offset phenomenon in which toner is transferred from the transfer paper S to the endless belt 100. It is configured as an application roller that applies an offset suppressing release agent such as silicone oil to the belt surface. The heat fixing device employing the above-described film heating method is, for example, a heat fixing device for a recording material carrying an unfixed toner image to be fixed in an image forming apparatus such as a copying machine, a laser beam printer (LBP), an electrostatic printer, and the like. It is effectively used as a device or a device for heating a material to be heated widely, such as a device for modifying a surface property by heating a recording material carrying an image, and a device for temporarily attaching.

In the apparatus having the endless belt 100, the belt moves more or less to one side or the other side in the direction of the rotation axis (perpendicular to the paper surface), and a displacement occurs. . As a cause of the positional deviation due to the belt shift, the degree of parallelism and twist of at least two winding members such as a roller around which the belt is wound are increased. It is difficult to prevent the above-described belt position shift only by improvement. Therefore, there is a detection ring type device as one of the belt shift control devices that automatically controls the position shift due to the shift of the belt within a predetermined allowable range. This is because a belt shift detection member (hereinafter referred to as a detection ring and a detection member) rotatably supported by at least one end of at least one winding member (roller) on which the endless belt is stretched and coming into contact with the widthwise end of the belt. Write)
And a belt tensioning member displacement means (roller end displacement means) for converting torque due to contact of the detection ring with the end of the rotating belt into displacement of the winding member, and detecting by contact with the belt. The rotational force T1 of the ring (indicated by reference numeral 109 in FIG. 10 as an example) is converted into a linear motion, and the winding member is displaced in a predetermined direction (here, downward displacement f) to move relatively to a balanced position. The belt shift is controlled by using the method described in
No. -314299.

[0005]

However, in a detection ring type belt shift control device, when the belt is not driven to rotate, the direction in which the winding member (the heating roller 102 in FIG. 10) is displaced when the detection ring acts. Usually, a winding member urging member (not shown) for applying an urging force f2 for displacing the winding member in a direction opposite to the vertical direction in FIG. 10 is provided. However, in this case, the pressing force f1 received by the film surface abutting member 104 from the spring 113 cancels the urging force f2 of the winding member urging member, which may cause a problem that the function of the belt shift control does not work. . Further, even if it functions well, due to the variation in the pressing force of the film surface contact member 104, when the film surface contact member 104 is an oil application roller, stable oil application cannot be performed, and application unevenness easily occurs, In the case of a cleaning member, the cleaning accuracy may deteriorate.

Further, the pivot 1 of the heating roller 102 described above.
Reference numeral 09 is displaced relative to a base frame (not shown), and is pressed by a spring 107 in a direction away from the fixing roller 101 (horizontal direction in FIG. 10), while the film surface contact member 104 is supported on the base frame side. As a result, the relative lateral distance between them also fluctuates, and the endless belt 1
The tension of 0 fluctuates, and the undulation of the belt fluctuates and becomes unstable. In this respect, unevenness in oil application is likely to occur in the case of an oil application roller, and cleaning accuracy is likely to deteriorate in the case of a cleaning member.

A first and a second object of the present invention is to stabilize the tension of an endless film and stabilize the function of a film surface contact member. Further, a third object is to stabilize the tension of the endless film and stabilize the function of the film surface contact member even when the deviation preventing mechanism includes a control wire and a winding portion. Further, the fourth object is to stabilize the tension of the endless film and to improve the function of the film surface contact member even if the film surface contact member is an oil application roller or an oil application felt for applying oil or the like to the film surface. The purpose is to achieve stabilization.

Further, a fifth object is to stabilize the tension of the endless film and stabilize the function of the film surface contact member even if the film surface contact member is a cleaning roller or a cleaning pad for cleaning the film surface. The purpose is to plan. Further, a sixth object is to attach a biasing member for applying a biasing force to the film surface contact member on a bracket supported by the winding member, so that a special component for providing the biasing member is not required, and the number of parts is reduced. The purpose is to reduce the design and design in a small space.
Further, a seventh object is to stabilize the tension of the endless film even when the endless film stretching mechanism according to any one of claims 1 to 6 is used as a heating device, and to provide a film surface contact member. The purpose of this is to stabilize the function of.

[0009]

According to a first aspect of the present invention, there is provided an endless film which is wound around at least two winding members and which rotates, and which is pressed against an outer peripheral surface of the endless film by receiving an urging force. And a film surface abutting member that applies tension to the endless film, whereby an urging member that applies an urging force to the film surface abutting member is supported by the winding member. It is characterized by. Therefore, the film surface contact member pressed against the outer peripheral surface of the endless film by the urging force is displaced integrally with the winding member. For this reason, the relative distance between the film surface contact member and the wrapping member does not change, the tension of the endless belt is stabilized, fluctuations such as waving of the belt are stabilized, and the function of the film surface contact member can be stabilized.

According to a second aspect of the present invention, there is provided the endless film stretching mechanism according to the first aspect, further comprising a shift preventing mechanism for preventing the endless film from shifting on the winding member. A film shift detecting member rotatably supported by at least one end of at least one of the winding members, and a film shift detecting member formed by a frictional force between the film shift detecting member and an endless film end hanging on the film shift detecting member. And a winding member end displacing means for converting the rotational movement of the film shift detecting member into a linear movement when a rotational torque is applied and displacing the end of the winding member in a predetermined direction. I do. Therefore, the film surface contact member, the winding member, and the shift prevention mechanism, which are pressed by receiving the urging force on the outer peripheral surface of the endless film, are integrally displaced. For this reason,
The relative distance between the film surface contact member and the wrapping member does not change, and at the same time, the shift prevention mechanism is operated properly, and simultaneously the tension of the endless belt is stabilized, so that the function of the film surface contact member can be stabilized.

According to a third aspect of the present invention, in the endless film stretching mechanism according to the second aspect, the winding member end displacement means comprises a control wire and a winding portion. Therefore, even when the deviation prevention mechanism includes a control wire and a winding portion, the relative distance between the film surface contact member and the winding member does not change, and the deviation prevention mechanism is appropriately operated, and simultaneously the tension of the endless belt is stabilized.
The function of the film surface contact member can be stabilized.

The invention according to claim 4 is the invention according to claims 1 to 3.
Wherein the film surface contact member is an oil application roller and / or an oil application felt for applying oil or the like to the surface of the endless film.

Therefore, even when the film surface contact member is an oil application roller or an oil application felt for applying oil or the like to the film surface, stable oil application to the endless film cannot be performed, and application unevenness can be prevented.

[0014] The invention of claim 5 is the first to third aspects of the present invention.
In the endless film stretching mechanism according to any one of the above, the film surface contact member is a cleaning roller and / or a cleaning pad for cleaning the end film surface. Therefore, even when the film surface contact member is a cleaning roller or a cleaning pad for cleaning the film surface, the cleaning accuracy of the endless film can be stabilized.

The invention according to claim 6 is the invention according to claims 2 and 3.
In the endless film stretching mechanism according to any one of the above, a winding member biasing member for displacing the winding member in advance in a direction opposite to a direction in which the winding member is displaced when the film shift detection member is operated is provided, and the film surface is provided. An urging member for applying an urging force to the contact member is mounted on a bracket supported by the winding member. Therefore, an urging member for applying an urging force to the film surface contact member is mounted on the bracket supported by the winding member. For this reason, a special part for providing the biasing member is not required, and the number of parts is reduced.
The freedom of layout increases.

According to a seventh aspect of the present invention, there is provided an endless film wound and held between at least two tension members and driven to rotate, and at least one of the winding members generates heat through the endless film or the endless film. A heating device for heating a material to be heated by generating heat from the film itself, comprising a mechanism for stretching an endless film according to any one of claims 1 to 6. Therefore, even when the endless film stretching mechanism according to any one of claims 1 to 6 is used as a heating device, the tension of the endless film is stabilized,
The function of the film surface contact member can be stabilized.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a heat fixing device 20 having an endless film stretching mechanism to which the present invention is applied, and a schematic configuration of an electrophotographic copying machine incorporating the heat fixing device 20. The results are shown in FIG. An electrophotographic copying machine (hereinafter, simply referred to as a copying machine) 1 shown in FIG. 9 includes a document setting section 2 at an upper portion of a copying machine main body 1a, an image forming section 3 below the same, and a plurality of lower sections. Paper feed section 4 and these paper feed sections 4
The image forming section 3 includes a transport section 8 for transporting the transfer paper P as a recording material to the image forming section 3, a paper discharge section 5 on the side of the image forming section 3, and a control section (not shown). The document setting section 2 includes a contact glass 6 serving as a document table and a pressure plate 7 covering the contact glass.

The image forming section 3 is provided with an exposure device 9 on an upper portion thereof, and the exposure device 9 causes the original table (contact glass) 6 to be exposed.
Image exposure corresponding to the upper document image is performed on the photosensitive drum 10. That is, the exposure device 9 uses the light source 19 to
The upper document is illuminated, and the reflected light is applied to the photosensitive drum 10 as an image carrier via mirrors 16 to 18, the lens 12, and the mirrors 13 to 15. At the same time, the original is scanned by moving the light source 19 and the mirrors 16 to 18 forming the movable optical system, so that the photosensitive drum 10 is exposed to an image.

The image forming section 3 forms a copy of an original image by a known electrophotographic image forming process, and includes a photosensitive drum 10, an exposing device 9, a charging charger 23, a developing device 24, and a transfer charger 25. , Separation charger 26, heat fixing device 20, cleaning device 2
1. It comprises a static elimination lamp 22. When a document is set and a start key (not shown) is pressed, the photosensitive drum 10 is driven to rotate by a driving unit (not shown) and is uniformly charged by the charging charger 23, and then the exposure of the document image by the exposure device 9 is performed. And an electrostatic latent image is formed. This electrostatic latent image is developed with toner in the developing device 20 to become a toner image. On the other hand, the transfer paper S is fed one by one from the paper supply unit 4, and the transfer paper S is transferred by the registration roller 27 between the photosensitive drum 10 and the transfer charger 25 and the separation charger 26 at an appropriate timing. The toner image on the photosensitive drum 10 is transferred to the transfer paper S by the action. The toner remaining on the photosensitive drum 10 without being transferred is removed by the cleaning device 21, and the photosensitive drum 10 whose surface has been cleaned is used for the next image formation.

The transfer paper S to which the toner image has been transferred is sent to the heat fixing device 20 by the guide section 28, and after the toner image is fixed in the heat fixing device 20,
The sheet is discharged out of the apparatus main body 1 a by the sheet discharge roller 29 and is stacked on the sheet discharge tray 5. The configuration of the above-described heat fixing device 20 is shown in FIGS. Heat fixing device 2 of FIG.
Reference numeral 0 denotes a frame 30 supported on the apparatus main body 1a side, in which the fixing roller 32, the heating roller 33, the pressing roller 34, and the fixing roller 32 and the heating roller 33 are wound around. An endless belt 31 as an endless film to be provided, and an oil application roller 35 that applies silicone oil, which is an obset suppressing release agent, to the outer surface of the endless belt 31 and imparts a predetermined tension to the belt are supported. ing.

The frame 30 has a longitudinal direction X (see FIG. 4) perpendicular to the paper surface, and an end plate 30 provided at the left and right ends thereof.
1 and a plurality of bar-shaped members 302 (only one is shown) that are long in the longitudinal direction X and that integrally connect both end plates 301 to each other. In addition, a movable frame 46 for pivotally supporting the oil application roller 35 is provided between inner wall surfaces of the both end plates 301, and the movable frame 46 is slidably supported on the both end plates 301. The endless belt 31 is wound around a fixing roller 32 and a heating roller 33. The base of the endless belt 31 is made of nickel having a thickness of 100 mm.
A 200 μm release layer of silicon rubber is formed on the surface of a thin film body having a thickness of μm, and is formed so as to have good thermal responsiveness. The base of the endless belt 31 may be made of polyimide.
It may be about 150 μm. The fixing roller 32 is rotatably supported at its left and right ends by a pair of bearings 322 (only one of which is shown in FIG. 1), and is driven to rotate clockwise n1 in the figure by driving means (not shown). The fixing roller 32 is formed by covering a core metal with a heat-resistant porous elastic body having a small thermal conductivity and a heat insulating action.

The pressure roller 34 is formed of silicone rubber, and thereby, the pressure roller 34 and the endless belt 3
The transfer paper S after the fixing of the toner image is smoothly discharged from the nip portion N. The endless belt 31
Below, a transfer paper S supporting the toner image T can advance to a nip portion N between the belt 31 and the pressure roller 34 without touching the endless belt 31.
3 is provided, and a discharge guide 67 is provided behind the nip portion N.
Is provided. The pressure roller 34 is rotatably supported by a pair of pressure roller bearings 38, and the bearings 38 are slidably fitted in the guide long grooves 40 of the end plate 301. The pressure roller bearing 38 receives a pressing force by a compression spring 37 having one end abutting on the lower end edge of the guide long groove 40, and applies the pressing force to the fixing roller 32 via the endless belt 31.
In addition, it is possible to fix the toner image on the transfer paper S by heating and pressing.

The heating roller 33 is formed by using an aluminum pipe and having a high thermal conductivity. Further, a heater 43 is built in a central hole 331 of the heating roller 33,
The heater 43 is supported via a heater bracket 42 extending from a bearing support portion 461 described later. A thermistor (not shown) is provided for the belt portion on the heating roller 33, and the heater 43 is controlled so that the belt temperature approaches the set temperature in accordance with the detected temperature.

As shown in FIGS. 1 to 4, the heating roller 3
3 has its left and right ends supported by a bearing support 461 via a pair of heating roller bearings 332. The bearing support 461 on the movable frame 46 side is formed with a vertical guide groove 44 formed in the slider 44.
The slider 44 is supported by the end plate 301 so as to be relatively displaceable. Here, the slider 44 has a rectangular shape, and its upper and lower edges are slidably engaged with a straight guide rail 45 formed on the end plate 301. The slider 44 is connected to the end plate 30
The spring 3 whose one end is supported by the spring receiver 303 formed at 1
6, the pressing force P1 is received, and the pressing force P1 is pressed in a direction away from the fixing roller 32 along the guide rail 45. For this reason,
A tension corresponding to the pressing force P1 of the spring 36 is applied to the endless belt 31 wound around the fixing roller 32 and the heating roller 33. Further, the bearing support portion 461 supported by the vertical guide groove 441 of the slider 44 is
41 is slidably fitted in the up-down direction, which is the longitudinal direction.

Here, the bearing support 461 is formed as a part of the movable frame 46. As shown in FIGS. 1 and 4, the movable frame 46 is formed so as to extend diagonally upward in FIG. 1 from the pair of left and right bearing support portions 461 and each bearing support portion 461 so as not to interfere with the end plate 301. Extending plate portions 462, a connecting long plate 464 for integrally connecting the extending plate portions 462 to each other, and each extending plate portion 462 extending from the left or right end side of the connecting long plate 464. And each roller receiving portion 463. Each extension plate portion 462 has a guide pin 47 projecting outwardly on the side of each end plate 301, and this guide pin 47 is loosely slidably fitted in the vertical pin groove 48 of the end plate 301. You. The width a of the vertical pin groove 48
Is formed to have a predetermined width larger than the maximum outer diameter of the guide pin 47, and a gap is provided. Thus, when the guide pin 47 and the movable frame 46 are slightly displaced in the horizontal direction, that is, in the belt extending direction E together with the slider 44, the vertical pin groove 48 and the guide pin 47 can be prevented from interfering with each other.

The slider 44 has a spring receiver 442 formed at the upper end thereof and opposed to the lower end of the vertical pin groove 48, and is provided between the spring receiver 442 and the guide pin 47 as a biasing member. The roller movable spring 49 is mounted with a compression bias. For this reason, the slider 44 is
When the movable frame 46 on the slider 44 is minutely displaced in the belt stretching direction E in accordance with the elastic force of
Moreover, the movable frame 46 can move relative to the slider 44 in the direction along the vertical guide groove 441, that is, in the belt contact / separation direction Y, in accordance with the elastic force of the roller movable spring 49.

A pair of left and right roller receiving portions 46 of the movable frame 46
3 has a vertical guide hole 51 formed therein. As shown in FIG. 8, each vertical guide hole 51 has a bearing member 52 slidably fitted in a belt contacting / separating direction Y which is a substantially vertical direction, and an oil application roller is provided between the pair of left and right bearing members 52. 3
5 is pivoted. Upper end of bearing member 52 and vertical guide hole 51
A press-adjustment spring 50 is mounted between the upper end of the spring and the upper end. The pressure adjusting spring 50 is an urging member that applies an urging force to the oil application roller 35.
That is, the endless belt 31 is attached so as to be elastically pressed toward the outer surface of the belt. Here, a pair of left and right roller receiving portions 463 of the movable frame 46 directly support the roller movable spring 49, and since the roller movable spring 49 is provided, there is no need to use a special component separately, and the number of components is reduced. , And can be designed in a small space, increasing the degree of freedom in layout.

Here, the elastic force of the pressure adjustment spring 50 is appropriately adjusted, and the dirt removal of the endless belt 31 by the oil application roller 35 is stably and efficiently performed. The oil application roller 35 is formed by covering a core metal with silicone oil and silicone rubber having good freshness. The heating roller 33 pivotally supported between the pair of left and right bearing supports 461 of the movable frame 46 has a shift prevention mechanism 60 for preventing the endless film from shifting near its front end. As shown in FIGS. 1, 2, and 5, the shift prevention mechanism 60 includes a detection ring 61 as a film shift detection member rotatably supported at the front end of the heating roller 33.
When the rotational torque T acts on the detection ring 61 due to the frictional force between the end of the endless belt 31 and the detection ring 612, the rotational movement of the detection ring 61 is converted into a linear movement to convert the heating roller 33 into a linear movement. And a take-up part 613 as a winding member end displacement means for displacing the end in the downward direction D.

The detection ring 61 is rotatably provided concentrically on a shaft portion on the front side of the heating roller 33.
The inner wall surface of the main portion 612 is substantially in sliding contact with the outer peripheral surface on the front end side of the heating roller 33, and the outer diameter thereof is set to be substantially the same as the outer shape of the heating roller 33. The main part 6
A stopper flange 611 protrudes from an outer end surface of the endless belt 12, thereby restricting excessive displacement of an end of the endless belt 31. Further, the outside of the stopper flange 611, the annular groove-shaped winding portion 6 is provided.
13 are integrally formed. One end of the control wire 54 is fixed to a part of the winding part 613, and a part of a portion extending from the fixed end is wound and supported by the winding part 613, and extends straight down. The bottom end is the end plate 3.
01 is fixed.

Here, the control wire 54 has flexibility,
In addition, the control wire 54 is formed of a material having a small tensile elongation, and the winding direction of the control wire 54 around the winding portion 613 is determined by the rotation torque T (see FIGS. 1 and 5) caused by the sliding of the detection ring 61 with the endless belt 31. Is set in the direction in which it is wound into the winding unit 613. The oil application roller 35 supported by the movable frame 46 is provided with an oil application felt 64 as an oil supply member that abuts on the roller and supplies silicon oil. Here, the oil application roller 35 remains supported by the movable frame 46, but the oil application felt 64 is detachably provided to enable replacement or oil supply. Next, FIG.
The operation of the heat fixing device 20 will be described.

When the copying machine 1 operates according to a known electrophotographic image forming process in order to form a copy of a document image, the heat fixing device 20 also performs a heat fixing operation in accordance with the image forming process. The toner image is fixed, and is discharged to the discharge tray 5 side. At this time, the endless belt 31 in the heat fixing device 20 is also driven to rotate clockwise n1. In the rotation driving process of the endless belt 31, the endless belt 31 is moved in the back end direction IN in the film width direction.
(See FIG. 2). In this case, the width (hanging amount) B (see FIG. 2) of the endless belt 31 on the front end side of the detection ring 61 is relatively small, and the frictional force between the endless belt 31 and the detection ring 61 becomes small. The acting rotational torque T is also small.
For this reason, the force P2 for pushing up the front end side of the heating roller 33 by the roller movable spring 49 is larger than the pulling-down force -P2 according to the winding force of the control wire 54 of the winding unit 613 due to the rotation torque T, Heating roller 33
Is the upper end wall s1 of the vertical guide groove 441 shown in FIG.
To reach a state where further lifting is prevented. That is, the front end side of the heating roller 33 is displaced upward U with the back end side as a fulcrum, and the heating roller 33 tears with respect to the axis of the fixing roller 32 and the pressure roller 34. In this state, the front end side of the endless belt 31 is relatively strongly wound around the heating roller 33, and the endless belt 31 moves toward the front end side OUT in the film width direction.

With the movement of the endless belt 31, the width B of the endless film 3l with respect to the detection ring 61 increases, and the endless film 31 and the detection ring 6 extend.
1 and the rotational torque T acting on the detection ring 61 also increases. This rotational torque T
Increases, the pulling-down force -P2 according to the winding force of the winding unit 613 increases. When the pulling-down force -P2 becomes larger than the pushing-up force P2 by the roller movable spring 49, the control wire 54 turns the winding unit 613. As a result, the front end side of the heating roller 33 is pulled down against the roller movable spring 49 and is displaced downward D.

When the pulling-down force -P2 continues to be larger than the pushing-up force P2 of the roller movable spring 49, the bearing supporting portion 461 pivotally supporting the heating roller 33 is moved to the position shown in FIG.
And is received by hitting the lower end wall s2 of the vertical guide groove 441 as shown in FIG.
That is, the front end side of the heating roller 33 is displaced downward D with the back end side as a fulcrum, and this displacement causes the heating roller 33 to tear with respect to the axis of the fixing roller 32 or the pressure roller 34. And in this state, the back end side of the endless belt 31 is relatively strongly wrapped around the heating roller 33,
The endless belt 31 is located in the back end direction I in the film width direction.
Return to N and move.

With the return movement of the endless belt 31 in the back end direction IN, the width B of the endless belt 31 with respect to the detection ring 61 decreases, and the frictional force between the endless belt 31 and the detection ring 61 decreases. Therefore, the rotation torque T acting on the detection ring 61 is also reduced. As the rotation torque T decreases, the winding portion 61
The pulling-down force -P2 corresponding to the control wire winding force of No. 3 decreases, and the pushing-up force P2 by the roller movable spring 49 becomes larger than this. Thereby, the control wire 54
While the heat roller 3 is being rewound from the winding unit 613.
3 is pushed up by the roller movable spring 49 and displaced upward. If the pushing-up force P2 by the roller movable spring 49 is larger than the pulling-down force -P2 on the front end side of the heating roller 33, the heating roller 33
Of the vertical guide groove 441 is received by the bearing support portion 461 pivotally supporting the vertical guide groove 441, and further pushing up is prevented. In this state, the endless film 3l returns and moves in the front end side direction OUT in the film width direction.

As described above, the rotational torque T acts on the detection ring 61 due to the frictional force with the endless film 3l.
The rotation torque T changes according to the magnitude of the width B of the endless belt 31 with respect to the detection ring 61,
As the width B of the endless belt 31 increases, the rotational torque T acting on the detection ring 61 increases, and the control wire winding force of the winding unit 613 increases. And
The front side of the heating roller 33 is displaced upward U and downward D due to the magnitude relationship between the pulling-down force -P2 corresponding to the winding force and the pushing-up force P2 of the roller movable spring 49, so that the direction in which the endless belt 31 leans toward the front end. The endless belt 31 that is displaced in the side direction OUT and the back end side direction IN, and consequently, can be controlled so as to maintain the endless belt 31 that is rotationally driven near the neutral position.

In controlling the direction in which the endless belt 31 shifts, the bearing support portion 461 for pivotally supporting the heating roller 33 includes the upper end wall s1 and the lower end wall s2 of the vertical guide groove 441.
Between the guide rails 4 on the end plate 301.
The pressing force P1 is received by the spring 36 in a direction away from the fixing roller 32 along the direction 5, and a slight displacement is made in the lateral direction. However, here, the movable frame 4 pivotally supporting the oil application roller 35 is used.
6 is a part of the heating roller 3 on a bearing support portion 461.
3 and there is no relative vertical and horizontal displacement between the oil application roller 35 and the heating roller 33. as a result,
Oil application roller 35 for endless belt 31 stretched and stretched between fixing roller 32 and heating roller 33
The contact state and the tension of the endless belt 31 do not fluctuate, and the waving state of the endless belt 31 changes, thereby preventing the oil application roller 35 from destabilizing the removal of dirt on the endless belt 31. In particular, the heating roller 33 and the oil application roller 35
Since there is no relative displacement in the up and down direction, even if the movable frame 46 side is vertically moved by operating the shift prevention mechanism 60,
The state of mutual contact between the endless belt 31 and the oil application roller 35 does not change, and the pressing force P3 (see FIG. 5) received by the oil application roller 35 from the pressure adjustment spring 50 cancels the pushing force P2 of the roller movable spring 49. Can be prevented, and the function of the belt shift control can be properly operated. Further, here, the endless film shift prevention mechanism 60 is operated properly, and at the same time, the oil application roller 35 is rotated.
Thus, the dirt removal of the endless belt 31 is stably and efficiently performed. Particularly, the dirt on the endless belt 31 can be efficiently removed by appropriately adjusting the elastic force of the pressing adjustment spring 50.

As described above, in the heat fixing apparatus of FIG. 1, the oil application roller 35 is pivotally mounted between the pair of left and right roller receiving portions 463 on the movable frame 46 side via the bearing member 52.
Although the oil application felt 35 is attached to the oil application roller 35, an oil application felt (not shown) may be mounted instead of the oil application roller 35, and the oil application felt may directly contact the endless belt. In this case, the same operation and effect as those of the heat fixing device of FIG. 1 can be obtained, and the configuration can be simplified.

Further, in the heat fixing device of FIG. 1, the oil application roller 35 is pivotally mounted on the pair of left and right roller receiving portions 463 via the bearing member 52. However, as shown in FIG.
The cleaning roller 65 may be pivotally mounted on the roller receiving portion 463. Also in this case, a vertical guide hole 51 is formed in a pair of left and right roller receiving portions 463 on the movable frame 46 side, and a bearing member 52 is fitted slidably in the vertical direction, that is, the belt contact / separation direction Y. A cleaning roller 65 is pivotally supported by 52. The cleaning roller 65 is formed by covering silicone rubber on a cored bar. The surface of the silicon rubber is formed so as to have a surface roughness greater than that of the endless belt 31 in order to remove dirt from the surface of the endless belt 31. In this case, the same operation and effect as those of the heat fixing device of FIG. 1 can be obtained. Further, a cleaning pad (not shown) may be attached in place of the cleaning roller 65, and the cleaning pad may be configured to abut on an endless belt. In this case, the same operation and effect as those of the heat fixing device of FIG. 1 can be obtained. Thus, the configuration can be simplified.

Further, the above-mentioned heating roller 33 has a central hole 33.
1, the heat of the heater 43 is transmitted to the transfer paper S via the heating roller 33 and the endless belt 31. Instead, an endless film (not shown) generates heat itself. In this case, the same operation and effect as those of the heat fixing device of FIG. 1 can be obtained.
Further, the above-described endless film stretching apparatus is a copying machine 1
Is applied as a heating and fixing device 20, but instead, it can be applied as a stretching mechanism of a photosensitive belt used in an image forming section of a copying machine (not shown). In this case, a film surface contact member For example, a cleaning roller can be used.

[0040]

As described above, according to the first aspect of the present invention, since the film surface contact member is displaced integrally with the winding member, the relative distance between the film surface contact member and the winding member changes. Instead, the tension of the endless belt is stabilized, fluctuations such as waving of the belt are stabilized, and the function of the film surface contact member can be stabilized. According to the second aspect of the present invention, since the film surface contact member, the winding member, and the shift prevention mechanism are integrally displaced, the relative distance between the film surface contact member and the winding member does not change, and the shift prevention mechanism is not changed. Of the biasing force between the film and the film surface contact member can be prevented, the proper operation of the deviation prevention mechanism, and the tension of the endless belt are stabilized, the fluctuation of belt waving etc. is stabilized, and the film surface contact The function of the member can be stabilized.

According to the third aspect of the present invention, even when the deviation preventing mechanism includes the control wire and the winding portion, the relative distance between the film surface contact member and the winding member does not change, and the deviation preventing mechanism is properly operated. At the same time, the tension of the endless belt is stabilized, and the function of the film surface contact member can be stabilized. According to the invention of claim 4, even when the film surface abutting member is an oil application roller or an oil application felt for applying oil or the like to the film surface, stable oil application to the endless film cannot be performed, and uneven application is caused. Can be prevented. According to the invention of claim 5, even when the film surface contact member is a cleaning roller or a cleaning pad for cleaning the film surface, the cleaning accuracy of the endless film can be stabilized.

According to the sixth aspect of the present invention, the urging member for applying the urging force to the film surface contact member is mounted on the bracket supported by the winding member. For this reason, a special component for providing the urging member is not required, the number of components is reduced, the design can be performed even in a small space, and the degree of freedom in layout increases. According to a seventh aspect of the present invention, even when the endless film stretching mechanism according to any one of the first to sixth aspects is used as a heating device, the tension of the endless film is stabilized, and the surface of the film used for the heating device is stabilized. The function of the contact member can be stabilized.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a heating and fixing device having a built-in endless film stretching mechanism to which the present invention is applied.

FIG. 2 is an enlarged cutaway sectional view of a main part of a heat roller of the heat fixing device in FIG.

FIG. 3 is a partially cutaway perspective view of the heat fixing device of FIG. 1 with one end plate removed;

FIG. 4 is a perspective view of the heat fixing device of FIG. 1;

FIG. 5 is a side view schematically showing a deviation prevention mechanism provided in the heat fixing device of FIG. 1;

FIG. 6 is a side view schematically showing a mechanism of a movable frame provided in the heat fixing device of FIG. 1;

FIG. 7 is a partial perspective view of a heat fixing device as a modification of the heat fixing device of FIG.

FIG. 8 is an enlarged front view of a cutout of a main part of a movable frame of the heat fixing device of FIG. 1;

9 is a partially cutaway schematic configuration diagram of a copier including the heat fixing device of FIG. 1;

FIG. 10 is a schematic side view of a conventional heat fixing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 copier 20 heat fixing device 31 endless belt 32 fixing roller 33 heating roller 35 oil application roller 46 movable frame 463 roller receiving portion 49 roller movable spring 50 biasing member 54 control wire 60 deviation prevention mechanism 61 detection ring 613 winding portion 65 Cleaning roller P2 Push-up force -P2 Pull-down force T Rotation torque

Claims (7)

[Claims] 1. An endless film that is wound between at least two winding members and rotates, and a film surface contact that applies tension to the endless film by being pressed against the outer peripheral surface of the endless film by being pressed. An endless film tensioning mechanism, comprising: a contact member; and a biasing member that applies a biasing force to the film surface contact member is supported by the winding member. 2. The endless film stretching mechanism according to claim 1, further comprising a shift prevention mechanism for preventing the endless film from shifting on the winding member, and wherein the shift prevention mechanism includes at least one of the shift prevention mechanisms. At least one end of the winding member is rotatably supported on the film shift detection member, and a rotational torque is applied to the film shift detection member by a frictional force between the film shift detection member and the endless film end hanging on the film shift detection member. A winding member end displacement means for converting the rotational movement of the film shift detecting member into a linear movement and displacing the end of the winding member in a predetermined direction. Installation mechanism. 3. An endless film tensioning mechanism according to claim 2, wherein said winding member end displacement means comprises a control wire and a winding portion. 4. The endless film stretching mechanism according to claim 1, wherein the film surface contact member applies an oil or the like to the surface of the endless film. 4. The endless film stretching mechanism according to claim 1, wherein the stretching mechanism is a felt. 5. The endless film stretching mechanism according to claim 1, wherein the film surface contact member is a cleaning roller and / or a cleaning pad for cleaning an end film surface. The mechanism for stretching an endless film according to claim 1, wherein: 6. The endless film stretching mechanism according to claim 2, wherein the winding member is previously displaced in a direction opposite to a direction in which the winding member is displaced when the film shift detecting member is operated. The winding member biasing member is provided, and a biasing member that applies a biasing force to the film surface contact member is mounted on a bracket supported by the winding member. An endless film stretching mechanism according to any one of the above. 7. An endless film which is wound and held between at least two tension members and is driven to rotate, and at least one of the winding members generates heat and generates heat via the endless film or the endless film itself. A heating device for heating a material to be heated by the above-mentioned method, and comprising the endless film stretching mechanism according to any one of claims 1 to 6.